The present invention relates to a package of welding wire such as solid wire or flux-cored wire, wherein the wire is coiled, with torsion around an axis of the welding wire in a pail container.
Pail containers are commonly used for large capacity reservoirs which accommodate 200 to 300 kg of welding wire. In the pail container the welding wire is coiled with torsion around an axis of the welding wire within its elasticity limit stress, for instance, 270 to 360 degrees per one loop of the wire. Thus, the welding wire in the pail container includes a force to release the torsion. Therefore, when the wire is not restricted, the wire has a tendency to jump toward an axial direction of the pail container. This frequently causes twining and tangling of the wire when drawing out the wire from the pail container. For solving this problem it is known, as described in Japanese published patent No. Sho 59-8474, that an annular pressing plate can be placed on the coiled welding-wire loops to push the wire downward.
FIG. 5 shows a cross-sectional view of welding wire filled in a pail container as shown in above mentioned Japanese published patent No. Sho 59-8474, wherein the wire is coiled in layers with torsion around an axis of the welding wire, and then drawn out from the pail container 1. The welding wire 5 forms a cylindrical cavity 4 inside the coiled wire 2. On the top of the coiled wire 2 an annular pressing plate 8 is placed for preventing the welding wire from jumping. In this case, an inner diameter of the annular pressing plate is slightly smaller than an inner diameter of the coiled wire, as necessary. The annular pressing plate is large enough for pushing the coiled wire. For instance, when inner diameters of ordinary pail containers are 500 mm or 650 mm, the inner diameter of the coiled wire is 340 to 460 mm, and annular pressing plates having inner diameters of 230 to 350 mm are adopted.
In the process of drawing out welding wire from a pail container in FIG. 5, the welding wire 5 is drawn out upwardly, wherein a separation point of the wire from the coiled wire 2 travels along the inner edge 9 of the annular pressing plate 8 at the top of the coiled wire 2. FIG. 6 is a plan view of a part of the pail container shown in FIG. 5, wherein a few turns of wire at the top of the coiled wire 2 are especially shown. Because the separation point of the welding wire 5 rotates along the inner edge 9 of the annular pressing plate 8, the welding wire is drawn out while being in contact with a next loop 10 nearly parallel thereto, and while traveling along the inner edge 9 of the annular pressing plate 8. Consequently, the annular pressing plate is slightly lifted when welding wire is drawn out at high speed, or rigidity of the welding wire is high. This may cause twining and tangling of the welding wire when the next loop 10, and moreover the succeeding loops 11, are drawn out into the cylindrical cavity 4 and the wire springs up in the cylindrical cavity due to release of the torsion around an axis of the welding wire.
In consideration of the above mentioned current status, the present invention is intended to offer a welding wire package which does not have the problem of twining and tangling even if welding wire is drawn out at high speed, or rigidity of the welding wire is high, and also which attains smooth feeding of welding wire to a welding location without bending of the wire.
Namely, the present invention is a welding wire package wherein welding wire with torsion around an axis of the welding wire is coiled in a pail container while a cylindrical cavity is defined therein. A wire pressing member is disposed on top of the coiled wire. The wire pressing member comprises a pressing part for pressing the coiled welding wire, and a wire guiding part having a hole of not more than 180 mm in diameter in a center of the wire pressing member for passage of the welding wire.
As a most preferable embodiment, the diameter of the hole of the wire guiding part is not less than 0.55T+10 (mm), where rupture strength of the welding wire is T (kgf). Also, a ratio W/T is in a range of 4 to 32, where weight of the wire pressing member is W (g) and rupture strength of the welding wire is T (kgf).